Internet Speed Calculator
Evaluate whether your broadband tier meets your household needs. Translate ISP marketing numbers into real-world download minutes for games, movies, and updates.
Overview: Evaluate whether your broadband tier meets your household needs. Translate ISP marketing numbers into real-world download minutes for games, movies, and updates.
How the Internet Speed Calculator Works Out Download Time
Real Speed = Advertised Speed × (1 - Protocol & Wi-Fi Overhead)Real-world speed accounts for TCP/IP headers, frame preamble, Wi-Fi channel contention, and signal degradation.
Convert 15 GB to bits
15 GB × 8 = 120,000,000,000 bits
Apply 90% efficiency
75 Mbps × 0.90 ≈ 67.5 Mbps of usable download throughput after TCP/IP overhead.
Divide bits by throughput
15 GB at 75 Mbps takes 29 min 38 sec (theoretical minimum 26 min 40 sec).
Internet Speed Calculator — Reference Table
Typical download durations for common file sizes, to sanity-check the result from the Internet Speed Calculator.
| File Size | 10 Mbps | 25 Mbps | 50 Mbps | 100 Mbps | 200 Mbps | 500 Mbps | 1 Gbps |
|---|---|---|---|---|---|---|---|
| 100 MB | 1 min 29 sec | 36 seconds | 18 seconds | 8.9 seconds | 4.4 seconds | 1.8 seconds | 889 ms |
| 500 MB | 7 min 24 sec | 2 min 58 sec | 1 min 29 sec | 44 seconds | 22 seconds | 8.9 seconds | 4.4 seconds |
| 1 GB | 14 min 49 sec | 5 min 56 sec | 2 min 58 sec | 1 min 29 sec | 44 seconds | 18 seconds | 8.9 seconds |
| 5 GB | 1 hr 14 min 4 sec | 29 min 38 sec | 14 min 49 sec | 7 min 24 sec | 3 min 42 sec | 1 min 29 sec | 44 seconds |
| 10 GB | 2 hrs 28 min 9 sec | 59 min 16 sec | 29 min 38 sec | 14 min 49 sec | 7 min 24 sec | 2 min 58 sec | 1 min 29 sec |
| 25 GB | 6 hrs 10 min 22 sec | 2 hrs 28 min 9 sec | 1 hr 14 min 4 sec | 37 min 2 sec | 18 min 31 sec | 7 min 24 sec | 3 min 42 sec |
| 50 GB | 12 hrs 20 min 44 sec | 4 hrs 56 min 18 sec | 2 hrs 28 min 9 sec | 1 hr 14 min 4 sec | 37 min 2 sec | 14 min 49 sec | 7 min 24 sec |
| 100 GB | 1 day 41 min | 9 hrs 52 min 36 sec | 4 hrs 56 min 18 sec | 2 hrs 28 min 9 sec | 1 hr 14 min 4 sec | 29 min 38 sec | 14 min 49 sec |
Frequently Asked Questions About Internet Speed Calculator
Why does my 100 Mbps plan download at 12 MB/s?
Because file downloads are measured in Megabytes (MB) and internet plans are sold in Megabits (Mb). 100 Mbps divided by 8 is 12.5 MB/s under ideal conditions.